Hyperthyroidism is a relatively common endocrine disorder that is particularly prevalent in older cats. It is a serious health condition that results from the hyperplastic growth of thyroid tissue and the over-production of thyroid hormone. Typical hyperthyroidism treatments include chronic administration of an antithyroid medication, surgical removal of the thyroid, and/or radioactive iodine therapy. These treatments are expensive and have their limitations and side effects. For example, as most antithyroid medications are administered orally, compliance is often compromised. Surgery requires anesthesia and is not necessarily an option for older felines, particularly felines that suffer from other diseases as well. Radioactive iodine therapy is available only in facilities licensed to use radioactive materials, and requires hospitalization of the felines until their levels of radioactivity are safe.
Since the production of thyroid hormone requires dietary iodine, methods have been developed to treat hyperthyroidism in cats that involve feeding diets with restricted iodine content. It would be desirable to supplement such iodine-restricted diets with ingredients that reduce iodine uptake by the thyroid gland and with ingredients that inhibit synthesis of thyroid hormone.